Predictive end-to-end management for SONET networks

ABSTRACT

A system and method is disclosed that allows for the monitoring, analyzing and reporting on performance, availability and quality of optical network paths. The correlation of PM parameter metrics to client connections, coupled with threshold-based alarm generation provides a proactive and predictive management, reporting and analyzing of the health and effectiveness of individual path connections to alert Operational Support (OS) staff and/or customers to signal degradation and impending Network Element (NE) failures. The system and method performs in real-time processing intervals required for alarm surveillance in a telecommunications network.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/074,388, entitled “Predictive End-To-End Management for SONETNetworks,” filed on Mar. 4, 2008 now U.S. Pat. No. 8,290,362, thedisclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The invention relates generally to network communications. Morespecifically, the invention relates to a system and method forpredictive end-to-end network management for optical networks employingmonitoring, correlating and alarming performance parameters.

A Synchronous Optical Networking (SONET) system includes switches,multiplexers and repeaters, all connected by optical fiber. SONETtopologies are typically configured as self-healing, dual-ring networksusing dual fiber optic cables.

The SONET physical layer is divided into four sublayers. The lowestsublayer is the photonic sublayer. The three remaining sublayerscorrespond to the sections, lines and paths. An optical fiber goingdirectly from any device to any other device is referred to as asection. A run between two multiplexers is referred to as a line and theconnection between a source node and a destination node with one or moremultiplexers and repeaters is referred to as a path. The sectionsublayer handles a single point-to-point fiber run, generating astandard frame at one end and processing it at the other. Sections canstart and end at repeaters, which amplify and regenerate the bits, butdo not change or process them. The line sublayer is concerned withmultiplexing multiple tributaries onto a single line and demultiplexingthem at the other end. To the line sublayer, the repeaters aretransparent. When a multiplexer outputs bits on a fiber, it expects themto arrive at the next multiplexer unchanged, no matter how manyrepeaters are used in between. The protocol in the line sublayer isbetween two multiplexers and deals with issues such as how many inputsare being multiplexed together and how. The path sublayer and protocoldeal with end-to-end issues.

SONET and Synchronous Digital Hierarchy (SDH) have a limited number ofdefined architectures. These architectures allow for efficient bandwidthusage as well as the ability to transmit traffic even when part of thenetwork has failed.

A major advantage of SONET networks is their standardized AutomaticProtection Switching (APS) schemes. SONET systems can be configured aspoint-to-point terminals, linear add-drop chains and rings. Two types ofself healing ring topologies are Unidirectional Path Switched Ring(UPSR) and Bi-directional Line Switched Ring (BLSR).

FIG. 1 shows a four node ring. Each node on the ring is connected to itsrespective adjacent nodes by two optical fibers, one transmits and onereceives. The outer fiber loop may be referred to as ring 1 and theinner fiber loop is referred to as ring 2. In this example a path(circuit) is to be set up between nodes A and C. The input at node Atravels clockwise on ring 1 and egresses at node C. The input to node Calso travels clockwise on ring 1. The signal egresses at node Acompleting the path, establishing communications between source node Aand destination node C. All that is required for the path to beoperational is the ring 1 fiber unidirectional path.

Ring 1 is the working path and ring 2 is the protection path. Protectionis facilitated by adding a bridging circuit at the SONET Network Element(NE) source node. Protection traffic travels anticlockwise on ring 2. Aselector switch is implemented at the SONET NE destination node whichchooses the signal that exits. Selection is made upon SONET PerformanceMonitoring (PM) path parameters such as Alarm Indication Signal (AIS),Loss of Pointer (LOP), Loss of Signal (LOS), Signal Degrade (SD), andothers.

FIG. 2 shows a fiber break between nodes B and C. When the break occurs,the receiver at node C ring 1 detects an Optical Carrier (OC) OC-N LOSand inserts an Alarm Indication Signal-Path (AIS-P) onto all affectedpaths. When a drop node (in this case node C) detects the AIS-P on theworking path, the selector performs a path switch to ring 2. Becausenode C is adjacent to the fiber break, all of its selectors will make apath switch. The output of node C on ring 1 has an AIS-P on all of itspath signals except for those added at node C.

Node A will not detect the fiber break LOS, but the receiver on ring 1will detect the AIS-P that is inserted onto the path at node C. Node Awill receive its signal from B on ring 2. Node A is not adjacent to thefiber break so all its path selectors will switch based upon pathintegrity of each individual path independent of the status of any otherpath. Each node in a SONET ring makes the decision to switchindependently without communicating to any of the other nodes.

Due to the large volume of PM parameter data possibly accumulated for anOC-N line, for example, a SONET OC-48 path from New York, New York toLos Angeles, Calif., having many lines, it is difficult to analyze allof the accumulated PM parameter data. Even in the absence of seriousfiber breaks, the amount of PM parameter data is voluminous. For slightpath deficiencies, statistical counters and metrics have not beenmanaged. What is desired is a system and method that provides a customerwith predictive end-to-end path management of his SONET networks.

SUMMARY OF THE INVENTION

The inventors have discovered that it would be desirable to have asystem and method that allows for the monitoring, analyzing andreporting on performance, availability and quality of optical networkpaths. The correlation of PM parameter metrics to customer paths,coupled with threshold-based alarm generation provides proactive andpredictive management, reporting, and analyzing of the status andeffectiveness of individual paths. Operational Support (OS) staff and/orcustomers may be alerted to signal degradation and impending NEfailures. The system and method performs in real-time processingintervals required for alarm surveillance in a telecommunicationsnetwork. Methods correlate and analyze PM parameter metrics and generatealarms using baseline thresholds.

One aspect of the invention provides a method for assessing the statusof a plurality of network provisioned end to end paths of a networkuser. Methods according to this aspect of the invention includeaccessing a network provisioned path database; selecting a provisionedend to end path of the network user from the database, the path being aring having a forward path including points of interest A_(client) andA_(network), and having a return path including points of interestZ_(client) and Z_(network), wherein: path point of interest A_(client)is an A-side near-end receive client facing reference obtained fromperformance monitoring parameters derived at the node A tributary cardgroup, path point of interest A_(network) is an A-side far-end receivenetwork facing reference obtained from performance monitoring parametersderived at the node Z optical line interface unit card group, path pointof interest Z_(client) is a Z-side near-end receive client facingreference obtained from performance monitoring parameters derived at thenode Z tributary card group, and path point of interest Z_(network) is aZ-side far-end receive network facing reference obtained fromperformance monitoring parameters derived at the node A optical lineinterface unit card group; for the path, identifying from the databasethe path source terminating node A and path destination terminating nodeZ; correlating the path nodes A and Z to physical ports at nodes A and Zfor monitoring the path points of interest A_(client) and A_(network);obtaining performance monitoring parameter data for the path points ofinterest A_(client) and A_(network); for a same performance monitoringparameter x, if non-zero A_(client) parameter x equals A_(network)parameter x, identifying that a problem is manifest in equipment of thenetwork user upstream of node A; for the same performance monitoringparameter x, if A_(network) parameter x is greater than A_(client)parameter x, identifying that a problem is manifest in path equipmentwithin the provisioned end to end path between nodes A and Z; repeating,for a plurality of remaining network provisioned end to end paths of thenetwork user, the elements of selecting a provisioned end-to-end path,identifying the path terminating nodes, correlating the path nodes formonitoring the path points of interest A_(client) and A_(network),obtaining performance monitoring parameter data for the path points ofinterest A_(client) and A_(network), identifying that a problem ismanifest upstream of node A, and identifying that a problem is manifestbetween nodes A and Z; and preparing a report recommending maintenanceof the network user's network provisioned end to end paths based on theperformance monitoring parameter data.

Another aspect of the method includes setting threshold values for eachperformance monitoring parameter x at path points of interest A_(client)and A_(network); if A_(client) parameter x and/or A_(network) parameterx is outside of its threshold value, observing A_(client) parameter xand/or A_(network) parameter x over an accumulation period whereinA_(client) parameter x and/or A_(network) parameter x values outside oftheir threshold values are counted; and if after the accumulationperiod, the count for A_(client) parameter x and/or A_(network)parameter x is determined to be increasing, alerting a degradingcondition for equipment upstream of path points of interest A_(client)and/or A_(network) respectively.

Another aspect of the method includes if, after the accumulation period,the count for A_(client) parameter x and/or A_(network) parameter x isdetermined to be not increasing, issuing a report for the path forparameter x that includes errors introduced by equipment upstream ofpath point of interest A_(client) and errors introduced by networkequipment defined between path points of interest A_(network) andA_(client).

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary dual-ring network.

FIG. 2 is the exemplary dual-ring network in FIG. 1 sustaining a dualfiber break.

FIG. 3 is an exemplary end-to-end path showing monitoring points ofinterest.

FIG. 4 is an exemplary end-to-end path management system framework.

FIGS. 5A, 5B and 5C is an exemplary list of Performance Monitoring (PM)parameters and definitions.

FIG. 6 is an exemplary end-to-end path management method.

FIG. 7 is an exemplary end-to-end path management status report.

DETAILED DESCRIPTION

Embodiments of the invention will be described with reference to theaccompanying drawing figures wherein like numbers represent likeelements throughout. Before embodiments of the invention are explainedin detail, it is to be understood that the invention is not limited inits application to the details of the examples set forth in thefollowing description or illustrated in the figures. The invention iscapable of other embodiments and of being practiced or carried out in avariety of applications and in various ways. Also, it is to beunderstood that the phraseology and terminology used herein is for thepurpose of description and should not be regarded as limiting. The useof “including,” “comprising,” or “having,” and variations thereof hereinis meant to encompass the items listed thereafter and equivalentsthereof as well as additional items.

The terms “connected” and “coupled” are used broadly and encompass bothdirect and indirect connecting and coupling. Further, “connected” and“coupled” are not restricted to physical or mechanical connections orcouplings.

The invention is not limited to any particular software languagedescribed or implied in the figures. A variety of alternative softwarelanguages may be used for implementation of the invention. Somecomponents and items are illustrated and described as if they werehardware elements, as is common practice within the art. However,various components in the system and method may be implemented insoftware or hardware such as FPGAs, ASICs and processors.

Embodiments of the invention provide methods, systems, and acomputer-usable medium storing computer-readable instructions formonitoring, analyzing and reporting on performance, availability andquality of optical network paths. The invention is a modular frameworkand is deployed as software as an application program tangibly embodiedon a program storage device. The application code for execution canreside on a plurality of different types of computer readable mediaknown to those skilled in the art.

Embodiments correlate SONET/Ethernet PM parameter data to indicate thehealth status of end-to-end SONET/Ethernet network paths. Ethernet iscarried over a SONET/SDH network via Generic Framing Procedure (GFP).GFP is a protocol that maps the client Ethernet packet data onto theSONET network. SONET PM parameter data and Ethernet specific PMparameter data is monitored. Client signals enter the network with orwithout errors and are transported across a network path during whichtime signal errors may be propagated or may be introduced. Embodimentspredict problems in network paths that may impact customer applicationsand provide proactive alerting mechanisms such as automatic maintenanceticket generation. Customers' network path status is visible viaWeb-based views and reports.

Embodiments sample a customer's SONET/SDH path at four distinct points,and coupled with threshold-based alarms for one or more PM parameters,provide effective management, monitoring, analyzing and reporting ofperformance, availability and the quality of each customer's path. Thecorrelated SONET PM data, paths, and customer data is made available toa reporting system. The reporting system generates a historical datatrend for customer access and viewing via a Graphical User Interface(GUI).

FIG. 3 shows a simplified SONET bidirectional end-to-end path connection301, from a source node A (path terminating node) NE to a destinationnode Z (path terminating node) NE. One or more nodes (B through Y) mayreside between the path terminating nodes A and Z and may form SONETsections and lines. The SONET network architecture between node A andnode Z may be a dual-ring configured as a UPSR, a BLSR using workingtraffic and protection traffic fibers, or other configurations. SONETrings provide a fault tolerant and flexible transmission architecture.

The A and Z path terminating nodes are NEs comprised of tributary cardgroups 303A, 303Z, 305Z, 305A which can map DSX and OC-N digital signallevels into synchronous Virtual Tributaries (VT) VT1.5s and DS3s intoSynchronous Transport Signals (STS-X) of the first level, STS-1. VT1.5sare mapped into STS-1s for transport across the network path. Thesynchronous nature of the VT1.5 and STS-1 allows for direct access tothe payload and facilitates efficient add/drop multiplexing andgrooming. The tributary card groups 303A, 303Z, 305Z, 305A convert anelectrical signal such as DS3 to an OC-N signal such as OC-12.Channelized Synchronous Payload Envelope (SPE) traffic from thetributary card groups 303A, 303Z, 305Z, 305A is transmitted to andreceived from SONET Digital Cross-Connects (DCC) 307A, 307Z, 309Z, 309A.The DCCs 307A, 307Z, 309Z, 309A terminate SONET and DSX signals andaccept optical OC-N signals and STS-1s, DS1s and DS3s. In a DCC, theswitching may be performed at any granularity, for example, STS-1,STS-3, and others, cross-connecting the constituent VTs between STS-Xterminations.

An exemplary OC-3 system can transport 84 DS1s, 3 DS3s or anycombination in-between. DS1s are interfaced to the SONET carrier usingtributary card groups (low speed modules). Each tributary card in agroup accepts DS1s and maps each DS1 into a VT1.5. The VT1.5s arecombined to form a Virtual Tributary Group (VTG). The VTGs aremultiplexed into an STS-1 and passed to Optical Line Interface Units(OLIU) 311A, 311Z, 313A, 313Z, 315Z, 315A, 317Z, 317A for multiplexingto the OC-3 line rate.

Four PM parameter data measuring points of interest are defined in eachend-to-end customer path (circuit), from node A to node Z and from nodeZ to node A. For the node A to node Z path direction, an A-side clientfacing reference A_(client) is obtained from PM parameters derived atthe node A tributary card group 303A and an A-side network facingreference A_(network) is obtained from PM parameters derived at the nodeZ OLIU cards 311Z, 313Z.

The connection between A_(client) and A_(network) (and similarly for theZ information) is made starting with the tributary card, and traversingthe cross-connect to locate where on the line side the signal leaves thenode. The same logic is performed at node Z. The value which is referredto as A_(network) is actually the PM parameter data that is retrieved atthe point on node Z′s line side card. The PM parameter data for thepoints of interest are the near-end receive (A_(client)) and far-endreceive (A_(network)).

For the node Z to node A path direction, a Z-side client facingreference Z_(client), is obtained from PM parameters derived at the nodeZ tributary card group 305Z and a Z-side network facing referenceZ_(network) is obtained from PM parameters derived at the node A OLIUcards 315A, 317A. Each PM parameter measuring point of interestA_(client), A_(network), Z_(client) and Z_(network) collects SONET PMparameter data derived at that location belonging to an associatedcustomer's path.

FIG. 4 shows an embodiment of a system framework 401. The framework 401includes a correlation engine 403 that includes a network topologycustomer information collector 405 and a PM parameter data collector407. The correlation engine 403 is coupled to a reporting engine 409 andan alerting engine 411. The reporting engine 409 is coupled to a Webaccess portal 413 for coupling with a network 415 such as the Internet.The alerting engine 411 is coupled to an automatic ticketing system 417for issuing maintenance tickets depending on the status of a customer'sprovisioned path(s). The network topology customer information collector405 is coupled to an inventory database 419 and a Database of Record(DBoR) 421 for the network 415. The network topology customerinformation collector 405 is configured to obtain a list of customersand their provisioned paths from the network 415.

For each customer provisioned end-to-end path, the inventory database419 stores the path data as a circuit traverses from its source node toits destination node. For example, a path connection may be provisionedfrom New York, New York to Los Angeles, Calif., establishing New York asthe source node (A) and Los Angeles as the destination node (Z) 423.During path provisioning, any number of intervening NEs may be employedbetween the path terminating nodes. The inventory database 419 maintainsall path information and the identity and location of each NE in thepath. The description describes paths contained within a single SONETring. However, paths traversing inter-connected rings may also beconsidered. In such cases, not every NE in a path will be known.Continuity from source to destination nodes is afforded by anabstraction of the NEs that physically connect SONET rings.

The tributary card groups and OLIU cards for nodes A and Z are polled inpredetermined time periods via a set of Transaction Language 1 (TL1)messages issued by the PM parameter data collector 407 to acquire PMparameter data for each customer's path connection 423 to be compared.TL1 is a traditional telecom language for managing and reconfiguringSONET NEs. The TL1 commands may depend upon the card vendor, thevendor's technology and the technology release number. There are anumber of specific TL1 retrieve PM commands that are functionallyequivalent covering DSX, OC-N, STS-N, TX and VTX. TL1 or other commandlanguages used by SONET NEs may be carried by other management protocolssuch as SNMP, CORBA and XML.

SONET network management for SONET NEs has a number of managementinterfaces. These are an electrical interface and a craft interface. Theelectrical interface sends SONET TL1 commands from a local managementnetwork physically housed in an office where a SONET NE is located toany location for monitoring. The SONET TL1 commands are used for localmanagement of that NE and remote management of other SONET NEs. Thecraft interface are for local technicians who can access a SONET NE on aport and issue commands through a dumb terminal or terminal emulationprogram running on a user's laptop.

SONET NEs have a large set of standards for PM data. The PM criteriaallow for monitoring not only the health status of individual NEs, butfor the isolation and identification of most network defects or outages.Higher-layer network monitoring and management software allows for theproper filtering and troubleshooting of network-wide PM so that defectsand outages can be quickly identified and responded to.

The PM parameter data acquired by the PM parameter data collector 407for each PM parameter measuring point of interest A_(client),A_(network), Z_(client) and Z_(network) may include the parameters shownin FIGS. 5A, 5B and 5C. As an example, there may be four Path CodingViolations (CV-P) acquired, one for each point of interest A_(client),CV-P, A_(network) CV-P, Z_(client) CV-P and Z_(network) CV-P for onepath. Any number of PM parameters may be acquired for the points ofinterest to perform the method.

The PM parameter data collector 407 acquires the path-level PM parameterdata from each terminating node NE for PM parameter data measuringpoints of interest A_(client), A_(network), Z_(client) and Z_(network)through the issuance of TL1 commands for each customer provisioned path.SONET paths are typically provisioned with Internet Protocol PerformanceMetrics (IPPM) to enable end-to-end path-level performance monitoring.Each path produces an accumulation of PM parameter data for each pointof interest A_(client), A_(network), Z_(client) and Z_(network). If 30PM parameters are employed, the framework 401 will acquire 30 PMparameters for each point of interest A_(client), A_(network),Z_(client) and Z_(network), for each customer provisioned pathconnection, in predetermined time periods, for example, a count every 15minutes.

The inventory database 419 containing each customer and each customer'spaths is mapped with each point of interest A_(client), A_(network),Z_(client) and Z_(network) for each path over time. While point ofinterest data acquisition is taking place, the correlation engine 403performs a comparison of the PM parameter data to determine the statusof each customer's paths.

FIG. 6 shows the method. The customer provisioned path database isaccessed (steps 601, 603). Each customer's paths are examined toidentify each path's respective terminating nodes A and Z (step 605,607).

Each point of interest A_(client), A_(network), Z_(client) andZ_(network) for a customer's path connection is identified (steps 607,609, 611, 613, 615) and is correlated with the identity of the physicalNE cards at node A and node Z (step 617). TL1 commands are issued by thePM data collector 407 to obtain the PM parameter data for each point ofinterest A_(client), A_(network), Z_(client) and Z_(network) (step 619).

A comparison of same PM parameter data is performed for each direction(step 621). For the path direction from node A to node Z, if a non-zeropoint of interest A_(client) PM parameter value (for example, A_(client)CV-P) is equal to the same PM parameter at point of interest A_(network)(for example, A_(network) CV-P),A_(client) parameter x=A_(network) parameter x,  (1)

the comparison indicates that errors (the non-zero A_(client) PMparameter value) reported in the PM parameter data were introduced byclient equipment upstream of node A (steps 623, 625). The conditionA_(client) parameter x>A_(network) parameter x cannot occur because PMparameter counts obtained from the downstream nodes (in this caseterminating node Z) are cumulative. The condition A_(client) parameterx<A_(network) parameter x is logically equivalent to A_(network)parameter x>A_(client) parameter x described below.

For the same PM parameter data, if a non-zero point of interestA_(network) PM parameter value (for example, A_(network) CV-P) isgreater than the same PM parameter at point of interest A_(client) (forexample, A_(client) CV-P),A_(network) parameter x>A_(client) parameter x,  (2)

the comparison indicates that the additional errors reported in theA_(network) PM parameter data were introduced by network equipmentduring transmission from node A to node Z (steps 627, 629).

For the case A_(network) parameter x>A_(client) parameter x, it ispossible that A_(client) is zero, but A_(network) is non-zero thusindicating a problem introduced by network equipment. However, whereA_(client) parameter x=A_(network) parameter x, the parameter should benon-zero. Also, the PM parameter points of interest are the “near-side,receive” parameters for a particular measuring point of interestA_(client), A_(network), Z_(client) and Z_(network).

If the comparisons in (1) and (2) are not true, no problem wasexperienced with that PM parameter (step 631).

For the path direction from node Z to node A, if a non-zero point ofinterest Z_(client) PM parameter value (for example, Z_(client) CV-P) isequal to the same parameter at point of interest Z_(network) (forexample, Z_(network) CV-P),Z_(client) parameter x=Z_(network) parameter x  (3)

the comparison indicates that errors (the non-zero Z_(client) PMparameter value) reported in the PM parameter data were introduced byclient equipment upstream of node Z (steps 633, 635, 637). The conditionZ_(client) parameter x>Z_(network) parameter x cannot occur because PMparameter counts obtained from the downstream nodes (in this caseterminating node A) are cumulative. The condition Z_(client) parameterx<Z_(network) parameter x is logically equivalent to Z_(network)parameter x>Z_(client) parameter x described below.

For the same PM parameter data, if a non-zero point of interestZ_(network) PM parameter value (for example, Z_(network) CV-P) isgreater than the same PM parameter at point of interest Z_(client) (forexample, Z_(client) CV-P),Z_(network) parameter x>Z_(client) parameter x  (4)

the comparison indicates that the additional errors reported in theA_(network) PM parameter data were introduced by network equipmentduring transmission from node Z to node A (steps 639, 641).

If the comparisons in (3) and (4) are not true, no problem wasexperienced with that PM parameter (step 643).

The PM parameter data for A_(client) parameter x, A_(network) parameterx, Z_(client) parameter x and Z_(network) parameter x (for example,CV-P) are stored and trend for predicting future failures and for reportpreparation (step 645), allowing for predictive and proactivemaintenance 417 of a customer's SONET assets.

PM parameter threshold values (operating regions) for A_(client)parameter x, A_(network) parameter x, Z_(client) parameter x andZ_(network) parameter x may be established on a per parameter basis toserve as baseline values. When a given PM parameter for A_(client)parameter x, A_(network) parameter x, Z_(client) parameter x and/orA_(network) parameter x (for example, CV-P) is outside of its respectivepredefined threshold value (steps 647, 649), the condition may beobserved over a predetermined accumulation period while the alertingengine 411 counts errors to see if the parameter data (error value) areincreasing over the PM parameter sampling periods. If the PM parametervalue continues to increase, an unresolved, deteriorating condition ispersisting and a determination is made to generate an alarm by thealerting engine 411 for the affected customer path. A maintenance ticketis issued by the auto-ticketing system 417 (step 651). If the PMparameter value remains outside of its threshold value but does notincrease over the predetermined accumulation period covering the PMparameter sampling periods, a report may be generated by the reportingengine 409 for the affected customer path.

Embodiments acquire PM parameter data at the points of interest andcorrelate the measurements and measurement differences with a respectivepath as a holistic view as opposed to acquiring PM parameter dataassociated with a given port. Path severities can be attributed to theresultant values as appropriate.

The predetermined thresholds are set in the alerting engine 411. Thethresholds are used to set error levels for each monitored point ofinterest PM parameter A_(client) parameter x, A_(network) parameter x,Z_(client) parameter x and Z_(network) parameter x, and may provideearly detection of performance degradation.

The method is repeated for each customer's path connections (steps 653,655) and for each customer in the path connection provisioned database419 (steps 657, 659, 661).

By sampling the PM parameter data for a customer's provisioned SONETpath, the four points of interest in conjunction with threshold-basedalarm generation allows for effective management, monitoring, analyzingand reporting of performance, availability and quality of opticalnetworks. The correlated PM parameter data, path, and customer data ispresented to the reporting engine 409 providing historical data andtrending to be available via a GUI.

FIG. 7 shows an exemplary result of the system and method indicating thethreshold crossings status for one customer's path connections(circuits) for a given PM parameter (x) measured for points of interestA_(client), A_(network), Z_(client) and Z_(network) for each samplingperiod. The A-side information includes a “Client Trouble Threshold”which is a user specified value for A_(client) parameter x clientthreshold, a “Client Value” which is an error count for PM parameter (x)introduced by the client equipment upstream of point of interestA_(client), a “Network Trouble Threshold” which is a user specifiedvalue for A_(network) parameter x network threshold, and a “NetworkTrouble Value” which is an error count for PM parameter (x) introducedby the network equipment between A_(network) and A_(client). Similarly,the Z-side information includes a “Client Trouble Threshold” which is auser specified value for Z_(client) parameter x client threshold, a“Client Value” which is an error count for PM parameter (x) introducedby the client equipment upstream of point of interest Z_(client), a“Network Trouble Threshold” which is a user specified value forZ_(network) parameter x network threshold, and a “Network Trouble Value”which is an error count for PM parameter (x) introduced by the networkequipment between Z_(network) and Z_(client).

One or more embodiments of the present invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

What is claimed is:
 1. A method for assessing the status of a pluralityof network provisioned end to end paths of a network user, comprising:accessing a network provisioned path database; selecting a provisionedend to end path of the network user from the database, the path being aring having a forward path including points of interest A_(client) andA_(network), and having a return path including points of interestZ_(client) and Z_(network), wherein: path point of interest A_(client)is an A-side near-end receive client facing reference obtained fromperformance monitoring parameters derived at the node A tributary cardgroup; path point of interest A_(network) is an A-side far-end receivenetwork facing reference obtained from performance monitoring parametersderived at the node Z optical line interface unit card group; path pointof interest Z_(client) is a Z-side near-end receive client facingreference obtained from performance monitoring parameters derived at thenode Z tributary card group; and path point of interest Z_(network) is aZ-side far-end receive network facing reference obtained fromperformance monitoring parameters derived at the node A optical lineinterface unit card group; for the path, identifying from the databasethe path source terminating node A and path destination terminating nodeZ; correlating the path nodes A and Z to physical ports at nodes A and Zfor monitoring the path points of interest A_(client) and A_(network);obtaining performance monitoring parameter data for the path points ofinterest A_(client) and A_(network); for a same performance monitoringparameter x, if non-zero A_(client) parameter x equals A_(network)parameter x, identifying that a problem is manifest in equipment of thenetwork user upstream of node A; for the same performance monitoringparameter x, if A_(network) parameter x is greater than A_(client)parameter x, identifying that a problem is manifest in path equipmentwithin the provisioned end to end path between nodes A and Z; repeating,for a plurality of remaining network provisioned end to end paths of thenetwork user, the elements of selecting a provisioned end-to-end path,identifying the path terminating nodes, correlating the path nodes formonitoring the path points of interest A_(client) and A_(network),obtaining performance monitoring parameter data for the path points ofinterest A_(client) and A_(network), identifying that a problem ismanifest upstream of node A, and identifying that a problem is manifestbetween nodes A and Z; and preparing a report recommending maintenanceof the network user's network provisioned end to end paths based on theperformance monitoring parameter data.
 2. The method according to claim1 wherein the performance monitoring parameter data is obtained from aperformance monitoring parameter database.
 3. The method according toclaim 1 wherein the performance monitoring parameter data is obtainedfrom network elements at the path points of interest A_(client) andA_(network).
 4. The method according to claim 1 wherein the performancemonitoring parameter data is obtained from network elements at the pathpoints of interest Z_(client) and Z_(network).
 5. The method accordingto claim 1 further comprising: setting threshold values for eachperformance monitoring parameter x at path points of interest A_(client)and A_(network); if A_(client) parameter x and/or A_(network) parameterx is outside of its threshold value, observing A_(client) parameter xand/or A_(network) parameter x over an accumulation period whereinA_(client) parameter x and/or A_(network) parameter x values outside oftheir threshold values are counted; if after the accumulation period,the count for A_(client) parameter x and/or A_(network) parameter x isdetermined to be increasing, alerting a degrading condition forequipment upstream of path points of interest A_(client) and/orA_(network) respectively.
 6. The method according to claim 5 furthercomprising if after the accumulation period, the count for A_(client)parameter x and/or A_(network) parameter x is determined to be notincreasing, issuing a report for the path for parameter x that includeserrors introduced by equipment upstream of path point of interestA_(client) and errors introduced by network equipment defined betweenpath points of interest A_(network) and A_(client).
 7. The methodaccording to claim 1 wherein the ring is a SONET ring.
 8. The methodaccording to claim 1 wherein obtaining performance monitoring parameterdata further comprises polling the path points of interest A_(client)and A_(network) via a set of Transaction Language 1 messages.
 9. Themethod according to claim 1 wherein the report includes a client troublethreshold crossings status for at least one of the points of interest.10. A tangible, non-transitory, computer-usable medium having storedthereon computer readable instructions for assessing a status of aplurality of network provisioned end to end paths of a network user,wherein execution of the computer readable instructions by a processorcauses the processor to perform operations comprising: accessing anetwork provisioned path database; selecting a provisioned end to endpath of the network user from the database, the path being a ring havinga forward path including points of interest A_(client) and A_(network),and having a return path including points of interest Z_(client) andZ_(network), wherein: path point of interest A_(client) is an A-sidenear-end receive client facing reference obtained from performancemonitoring parameters derived at the node A tributary card group; pathpoint of interest A_(network) is an A-side far-end receive networkfacing reference obtained from performance monitoring parameters derivedat the node Z optical line interface unit card group; path point ofinterest Z_(client) is a Z-side near-end receive client facing referenceobtained from performance monitoring parameters derived at the node Ztributary card group; and path point of interest Z_(network) is a Z-sidefar-end receive network facing reference obtained from performancemonitoring parameters derived at the node A optical line interface unitcard group; for the path, identifying from the database the path sourceterminating node A and path destination terminating node Z; correlatingthe path nodes A and Z to physical ports at nodes A and Z for monitoringthe path points of interest A_(client) and A_(network); obtainingperformance monitoring parameter data for the path points of interestA_(client) and A_(network); for a same performance monitoring parameterx, if non-zero A_(client) parameter x equals A_(network) parameter x,identifying that a problem is manifest in equipment of the network userupstream of node A; for the same performance monitoring parameter x, ifA_(network) parameter x is greater than A_(client) parameter x,identifying that a problem is manifest in path equipment within theprovisioned end to end path between nodes A and Z; repeating, for aplurality of remaining network provisioned end to end paths of thenetwork user, the elements of selecting a provisioned end-to-end path,identifying the path terminating nodes, correlating the path nodes formonitoring the path points of interest A_(client) and A_(network),obtaining performance monitoring parameter data for the path points ofinterest A_(client) and A_(network), identifying that a problem ismanifest upstream of node A, and identifying that a problem is manifestbetween nodes A and Z; and preparing a report recommending maintenanceof the network user's network provisioned end to end paths based on theperformance monitoring parameter data.
 11. The tangible computer-usablemedium according to claim 10 wherein the performance monitoringparameter data is obtained from a performance monitoring parameterdatabase.
 12. The tangible computer-usable medium according to claim 10wherein the performance monitoring parameter data is obtained fromnetwork elements at the path points of interest A_(client) andA_(network).
 13. The tangible computer-usable medium according to claim10 wherein the performance monitoring parameter data is obtained fromnetwork elements at the path points of interest Z_(client) andZ_(network).
 14. The tangible computer-usable medium according to claim10, wherein the method further comprises: setting threshold values foreach performance monitoring parameter x at path points of interestA_(client) and A_(network); if A_(client) parameter x and/or A_(network)parameter x is outside of its threshold value, observing A_(client)parameter x and/or A_(network) parameter x over an accumulation periodwherein A_(client) parameter x and/or A_(network) parameter x valuesoutside of their threshold values are counted; if after the accumulationperiod, the count for A_(client) parameter x and/or A_(network)parameter x is determined to be increasing, alerting a degradingcondition for equipment upstream of path points of interest A_(client)and/or A_(network) respectively.
 15. The tangible computer-usable mediumaccording to claim 14 further comprising if after the accumulationperiod, the count for A_(client) parameter x and/or A_(network)parameter x is determined to be not increasing, issuing a report for thepath for parameter x that includes errors introduced by equipmentupstream of path point of interest A_(client) and errors introduced bynetwork equipment defined between path points of interest A_(network)and A_(client).
 16. The tangible computer-usable medium according toclaim 10 wherein the ring is a SONET ring.
 17. The tangiblecomputer-usable medium according to claim 10 wherein obtainingperformance monitoring parameter data further comprises polling the pathpoints of interest A_(client) and A_(network) via a set of TransactionLanguage 1 messages.
 18. The tangible computer-usable medium accordingto claim 10 wherein the report includes a client trouble thresholdcrossings status for at least one of the points of interest.